Forces acting against membranes

Question 1

The cell membrane separates the

Answer 1

ECF and ICF

Question 2

Cell membrane is responsible for maintaining

Answer 2

the difference in composition between the ECF and ICF

Question 3

There is no barrier to

Answer 3

water movement

Question 4

Ions can pass through the

Answer 4

capillary wall

Question 5

K+ is high in…… and low in ….

Answer 5

ICF

ECF

Question 6

Na+ is low in …. but high in ….

Answer 6

ICF

ECF

Question 7

Cell membrane is a ………. barrier

Answer 7

selective

Question 8

Permeability can…

Answer 8

vary

Question 9

head of a phosphoplipid is

Answer 9

hydrophilic and lipophobic

Question 10

tail of a phospholipid is

Answer 10

hydrophobic and lipophilic

Question 11

There is also a difference in charge across the cell membrane. this creates….

Answer 11

an electrical gradient

Question 12

To diffuse through the lipid bilayer molecules need to be

Answer 12

small
lipophilic
UNCHARGED

Question 13

water can pass through

Answer 13

aquaporins

Question 14

Voltage-gated channels

Answer 14

open/close in response to alterations in the membrane electrical potential (charge difference either side of the membrane)

Question 15

Ligand gated channels

Answer 15

open/close when they blind a chemical such as neurotransmitter or hormone to a receptor binding site on the channel protein

Question 16

Movement of molecules against their electrochemical gradients requires energy (ATP) and is known as

Answer 16

active transport

Question 17

H2O is inversely related to the

Answer 17

concentration of solute

Question 18

the more solute particles there are in solution - the more they will ………. H20

Answer 18

displace

therefore lowering the concentration of h20

Question 19

DIFFUSION

If a solution of different concentration is separated by a membrane permeable to water AND solute - then after time both will end up with equal ……. and equal ……..

Answer 19

concentration and volume

Question 20

If a solution of different concentration is separated by a membrane permeable ONLY to water - then after a time it will end up with…

Answer 20

equal concentrations either side of the membrane but

DIFFERENT VOLUMES

Question 21

Osmotic pressure

Answer 21

the pressure required to prevent water movement

Question 22

Osmolarity

Answer 22

measures the concentration of biological solutions in unit of OSMOLES and describes the number of particles/L in solution

Question 23

Normal human plasma osmolarity

the same as within cells

Answer 23

285 mOsmol/l (often 300)

Question 24

The cell volume at any time is dependent on the concentration of….

Answer 24

non-penetrating solutes on either side of the membrane

Question 25

Non-penetrating solutes

Answer 25

ECF = Na+ Cl-

ICF = K+

Question 26

Osmolarity

Answer 26

total number of particles in solution

Question 27

Tonicity

Answer 27

number of non-penetrating particles in solution

Question 28

tonicity is much more important as it determines

Answer 28

cell volume

Question 29

An iso-osmotic solution has

Answer 29

the same total number of solute particles as ECF (plasma)

Question 30

Hypo-osmotic

Answer 30

solutions with fewer total solute particles

Question 31

Hyper-osmotic

Answer 31

solution with greater number of total solute particles

Question 32

hypotonic

Answer 32

solutions with FEWER non-penetrating solute particles

Question 33

hypertonic

Answer 33

solution with greater number of non-penetrating solute particles

Question 34

cells in a hypotonic solution will

Answer 34

swell

water enters

Question 35

cells in a hypertonic solution will

Answer 35

shrink

water leaves